Speaker
Description
This project focuses on the development of suitable metallic targets for the in-core neutron irradiation of enriched lanthanide materials (e.g., Yb-176 and Gd-160) in a commercial nuclear power plant in Switzerland, enabling a reliable supply of medical-use of radiolanthanides (i.e., Lu-177 and Tb-161, both applied in Targeted Radionuclide Therapy). To achieve this, the project proposes to exploit the existing Aeroball core monitoring system (AMS; used for routine neutron flux measurements inside the reactor) as an insertion pathway for specially designed Gd and Yb target spheres.
Target materials were developed as Pd-based alloys doped with the selected lanthanoid element (Pd-Gd alloys were the first ones investigated). These are synthesized via hydrogen-mediated high temperature treatment [1] and must comply with the dimensional and mechanical specifications required by the AMS. Optimization efforts focused on key processing parameters, including composition, temperature, and heat treatment conditions, with the aim of enhancing both mechanical integrity and irradiation stability. Structural and microstructural characterization using X-ray diffraction and electron microscopy revealed the formation of a single, stable Pd-rich phase at a Pd-to-Gd ratio of 5:1, along with a homogeneous elemental distribution throughout the bulk volume. Mechanical testing through indentation and punch experiments suggested sufficient robustness to withstand stresses associated with the insertion into the AMS pipelines. Based on these results, spherical targets were successfully fabricated by arc melting under an Ar atmosphere, while preserving the optimized material features.
The produced spheres will then undergo neutron irradiation tests at the Swiss Spallation Neutron Source (SINQ) at PSI to evaluate the radiation hardness and to quantify radionuclide production yields. In a final step, a suitable chemical separation and purification strategy will be devised in order to obtain high-purity, non-carrier-added 177Lu and 161Tb suitable for radiopharmaceutical applications. This contribution outlines the current progress of the RAPIC project, which aims to establish a scalable and sustainable production route for key radiolanthanides in commercial nuclear power plants, ultimately improving their availability in Switzerland and internationally.
[1] H. Schulz et al., Z. anorg. allg. Chem. 357 (1968) 299-313